6. Which of the following statement on the PPP theory is NOT correct? A) The RPPP model is concerned with the rate of change" in the exchange rate. B) If the real exchange rate is 1, it means that the APPP condition is met. C) The RPPP model predicts that any change in the differential rate of inflation between two countries tends to be offset over the long run by the change in the interest rate. D) The APPP model is helpful when testing how appropriate the current spot exchange rate is